Officials in northwest Pakistan say an explosion near a polio vaccination team has killed two people and wounded 13 others.

Earlier reports said six people were killed in the blast Monday in a village outside of the provincial capital of Peshawar. The toll was revised after authorities received new information from a local hospital

Pakistan is one of three countries in the world where polio is still endemic.

The Global Eradication Initiative says eight new cases of polio were reported in northwest Pakistan last week.

One of the reasons polio remains prevalent is that militants who oppose the anti-polio campaigns often target the workers and threaten people who want to have their children vaccinated.